lgr

Another implementation of the logger with levels.

Install

go get github.com/va-slyusarev/lgr

Levels

In total 4 levels of logging are used:

// Levels.
const (
	DEBUG = "DEBUG"
	INFO  = "INFO"
	WARN  = "WARN"
	ERROR = "ERROR"
)

Each level has a priority, and if the current level is higher in priority than the priority of the message, it will not be printed.

Format

The format of the output messages can be configured using the template text/template. There are 4 predefined templates:

const (
	XSmallTpl = `{{ if .Prefix }}{{ printf "%s: " .Prefix }}{{ end }}{{ .Message }}`
	SmallTpl  = `{{ printf "[%-5s] " .Level }}{{ if .Prefix }}{{ printf "%s: " .Prefix }}{{ end }}{{ .Message }}`
	MediumTpl = `{{.TS.Format "2006/01/02 15:04:05" }} {{ printf "[%-5s] " .Level }}{{ if .Prefix }}{{ printf "%s: " .Prefix }}{{ end }}{{ .Message }}`
	LargeTpl  = `{{.TS.Format "2006/01/02 15:04:05.000" }} {{ printf "[%-5s] " .Level }}{{ printf "{%s} " .Caller }}{{ if .Prefix }}{{ printf "%s: " .Prefix }}{{ end }}{{ .Message }}`
)

Standard templates have aliases for use as flag parameters:

• XSmallTpl - XSmallTpl or xs
• SmallTpl - SmallTpl or sm
• MediumTpl - MediumTpl or md
• LargeTpl - LargeTpl or lg

Use case

package main

import (
	"flag"

	"github.com/va-slyusarev/lgr"
)

var message = flag.String("msg", "hello lgr!", "Logger message.")

func main() {
	flag.Var(lgr.Std.Level, "l", "Logger level.")
	flag.Var(lgr.Std.Prefix, "p", "Logger prefix.")
	flag.Var(lgr.Std.Template, "t", "Logger template.")
	flag.Parse()

	lgr.Debug(*message)
	lgr.Info(*message)
	lgr.Warn(*message)
	lgr.Error(*message)
}

Run

 go run main.go -l=WARN -p=ex -t=lg

You'll see something like this

2006/01/02 15:04:05.000 [WARN ] {_example/test.go:19} ex: hello lgr!
2006/01/02 15:04:05.000 [ERROR] {_example/test.go:20} ex: hello lgr!

See _example